I'll attach 3 pics to this post.
Pic 1 is the wire brush somewhat loaded-up with stripping residue. This is actually not that much (you can load the brush up a *lot* more when the residue is wetter), but was beginning to leave 'clumps' behind, and is enough to illustrate.
Pic 2 is using the plastic bag to strip the residue from the brush.
Pic 3 is the brush post-cleaning. As you can see, this works well.